Well, if you are using 1x1 pixels only it is ok. 2x2 pixels only is ok too but if you are mixing 1x1 and 2x2 together it does not really fit and it looks bad.
1x1 pixels are bad by itself, nor the 2x2 are so. What's ugly is when you mix both. Since they have different structure they tend to result not very well when you mix'em.